Skin Cancer Prevention Strategies: TRIED, TRUE, & NEW

By Ronald L. Moy, MD, and Shannon Famenini

Skin cancer is the most common cancer in the US. In 2013, more than two million people will be diagnosed with nonmelanoma skin cancers (NMSC),1 and almost 77,000 will develop potentially deadly melanomas.2 The total direct cost associated with the treatment for NMSC, primarily basal and squamous cell carcinomas, was $1.4 billion in 2004.3

Risk factors for skin cancer include fair complexion, weakened or suppressed immune systems, family history and genetic predisposition, having many moles or any typical moles, and a history of sunburns or skin cancer.4 Overall risk increases with age and ultraviolet (UV) radiation exposure. Additionally, some people simply have decreased DNA repair capability. For example, xeroderma pigmentosum patients have a rare genetic defect that prevents their DNA repair enzymes from undoing the damage caused by UV radiation, leaving them highly vulnerable to skin cancers.

Despite all these potential risk factors, skin cancer remains one of the most preventable diseases. The vast majority of the time, it can be avoided by protecting the skin from UV radiation emitted by the sun and tanning machines. Some effective protection methods include avoiding UV tanning; shade-seeking, especially between 10 AM and 4 PM; wearing protective clothing, and using sunscreen. There are also many other effective forms of skin cancer prevention. Everyone should be aware of the following tried and true or new prevention methods.

Prevention Strategy: Sunscreen Use

Sunscreens protect against skin cancer by deflecting or absorbing UV radiation, keeping it from reaching the skin and causing DNA damage. Consistent sunscreen use has been shown to result in significantly fewer new precancers, squamous cell carcinomas, and melanomas.5,6 Although most public health agencies recommend reapplying sunscreen every 2-3 hours, one study showed that doing a first reapplication after 20 minutes outdoors significantly reduces UV exposure.6 Some experts now recommend applying sunscreen both 30 minutes before UV exposure, and again after 15 to 30 minutes of continuous UV exposure. Further reapplications should be done after another two hours outdoors, or immediately after swimming or heavy sweating.

It’s also essential to apply a sufficient amount of sunscreen. Most people simply apply too little. A 2012 study suggested that a double application might help users attain the thickness needed to achieve the SPF (sun protection factor) value on the label.7 But applying enough sunscreen is just part of the equation, since only broad-spectrum (UVA- and UVB-filtering), high-SPF sunscreens (SPF 15+ for brief daily sun exposures and SPF 30+ for extended or intense exposures) can prevent or significantly reduce UV-induced skin damage.8 New FDA labeling regulations, which permit manufacturers to use the term “broad-spectrum” only on products containing sufficient UVA and UVB protection, should help consumers find appropriate sunscreens.

Prevention Strategy: Your Diet

Some research has shown that diets low in fat and high in fruits and vegetables can reduce the risk of all cancers, including skin cancer. In the 1990’s, Black and colleagues declared that a lowfat diet was associated with fewer actinic keratoses (common skin precancers) and NMSCs in skin cancer patients,9,10 while in 2004, subjects treated with an antioxidant derived from a fern experienced less redness and DNA damage following UV exposure.11 Antioxidants are substances such as vitamin C or E that remove potentially damaging toxins called “free radicals” from the body, and fruits and vegetables are full of these substances.

Prevention Strategy: Topical DNA Enzymatic Therapy

Our skin cells have built-in protective mechanisms that use DNA repair enzymes, which are molecules that prompt chemical changes, to repair UV damage. Scientists can now encapsulate such enzymes in certain fat cells so that they can be topically applied, allowing them to penetrate the skin and supplement its natural protective abilities. Topically applied DNA repair enzymes can reverse free radical damage caused by UV exposure and decrease the number of gene errors (mutations) that can lead to cancers.12,13 Although these enzymes are not FDA approved for the prevention of skin cancer, evidence suggests they can prevent precancerous lesions such as actinic keratoses.

Prevention Strategy: Retinoids

Retinoids, which are vitamin A derivatives, may prevent skin cancer in people particularly vulnerable to skin cancers.14,15,16 The oral retinoid isotretinoin(Roaccutane) improves wrinkles and other sun-induced skin damage, while actinic keratoses and basal cell carcinomas treated with the topical retinoid tretinoin, sometimes marketed as Renova or Retin-A,17,18,19 have completely regressed. Although such results may be temporary,20 tretinoin .05 percent does reduce some signs of skin aging (such as fine facial wrinkles, brown spots, and roughness) associated with chronic sun exposure. Used with topical DNA repair enzymes, it may help treat actinic keratoses and prevent basalcell and squamous cell carcinomas.

Prevention Strategy: Resurfacing Procedures

The use of resurfacing procedures and acid peels to treat skin precancers and prevent skin cancer has produced promising results — and fewer recurrences 21,22 than treatment with the topical chemotherapy drugs 5-fluorouracil and imiquimod.23,24 Dermabrasion, a resurfacing technique that uses abrasives to remove the top layers of the skin (which often contain many precancerous cells), and trichloroaceticacid peels have been used for years to treat severe actinic damage and prevent its progression to squamous cell carcinoma. More recently, treatment with fractional lasers, which permit a very careful and controlled delivery of light, has also reduced the number of actinic keratoses. One fractional laser is FDA-approved for this purpose.25,26,27

Conclusion

While more research on some of the newer strategies remains to be done, all of these methods should be considered when you’re exploring ways to prevent skin cancer.

Ronald L. Moy, MD, practices dermatology, Mohs micrographic surgery, and cosmetic surgery in Beverly Hills, CA. Dr. Moy completed his residency training at UCLA and his surgical fellowship with Dr. John Zitelli in Pittsburgh. He has been Editorin- Chief of Dermatologic Surgery, President of the American Society for Dermatologic Surgery and is a Past President of the American Academy of Dermatology. Dr. Moy is a Vice President of The Skin Cancer Foundation.

Shannon Famenini received her BA in biology from UCLA in 2009 and will graduate from the David Geffen School of Medicine in 2014. She is currently doing a clinical research fellowship at Kaiser ermanente Los Angeles Medical Center as well as assisting Dr. Moy in clinical studies.